Percussive tool



L. C. BAYLE'S.

PERCUSSIVE TOOL.

APPLlCATlON FILED APR. 6, 1920.

1,411,253, I Patented Apr. 4, 1922.

INVEIV TOR MW. (2. W

To all whom it may 00mm.-

umran STATE-S." PATENT. OFFICE.

IlEWIS c. BAYLES, or EAs'roN, PENNSYLVANIA, AssroNoaro INGERSOLL-RAND COMPANY, or JERSEY CITY, NEWJERSEY, AconroRA'rIoN or NEW JERSEY.

' rnncussrvn TOOL.

Be it known that I, Lnwrs CfBAYLEs, a

citizen of the United States, residing at Easton, in the county of Northampton and State of Pennsylvania, have invented a certain new and useful Improvement in Percussive Tools, of which the following is a speclfication.

This invention relates to percussive tools 'but more particularly to that type'o'ftool in which constant fluid pressure is supplied to one forwardly driving face-of a differential reciprocating piston constituting the hammer, the distribution of motiveufluid to the other faces of the piston-being suitably controlled and the exhaust being controlled at least in part by a suitable pressure actuated valve.

In a tool of this type it is desirable to always permit the piston. to finish its'full stroke before admitting air to reverse it, and

furthermore avoid a condition in which air be admitted to either end of the cylinder until the valvehas moved andIclosed the exhaust to that end of the'cylinder. This prevents air from entering the cylinder and escaping through the exhaust before the exhaust is closed.

The invention is shown in one of its preferred forms in the accompanying drawings, n which- Figure 1 is a diagrammatic longitudinal sectional view of so much of a percussive tool as willserve to illustrate the invention with the piston at the beginning of its forward stroke, and

Figure 2 is a similar view showing the piston having finished its forward stroke and about to return on its rearward stroke.

Referring to the drawings A represents diagrammatically a cylinder of a percussive tool having a main forward bore B and a rearward bore C of smaller diameter.' A portion of the shank of the drill steel is indicated at D. A differential piston reciprocates in the cylinder and is provided I Specification'of Letters Patent.

920. Serial No."371,594.

Patented Apr. 4, 1922.

with the main head E fitting the main bore B and a shank or extension preferably formed with an intermediate reduced neck F connecting the portions G and H ofthe shank of full diameter fitting the smaller bore C.

Fluid pressure is admitted to the cylinder at the inlet J and passes to the smaller' bore through the port K so'that fluid pressure is constantly maintained on the rearward end face L of the reduced piston shank.

Suitable ports and passages are provided,

controlled by the portion H of piston shank for distributing motive fluid to theforward and rearward ends of the main bore B, and

exhaust ports T andU adapted to communicate with the port S leading to atmosphere are provided for the main bore controlled "by a fluid actuated valve-mechanism shown in this instance as a valve P operating in the valve chest Q and actuated by fluid pressure.

The valve mechanism exemplified by the valve P not onlycontrols the exhaust means for the main bore B butincludes means for I retarding the admission of fluid to the ends of the main bore B until the valve has moved and closed the exhaust at that end of the cylinder. The valve mechanism P also prevents the admission of fluid to either end of the main bore B until the piston has practically finished its stroke, and the valve is thrown.

the above described features of my invention, an admission passage V is provided from the inlet J to the port IV- in the smaller bore C, andanother passage X leads from the port Y in the smaller bore C to a 'ort Z at the rear end of the valve chest so that motive fluid for actuating the valve P is admitted to the valve chest and the rear end face a of the valve is subjected to fluid pressure. An admission passage 1) leads from a porta in the smaller bore C to a port (Z at the forward end of the valve chest Q so that the forward end face 6 of the valve In order to secureme'ans for carrying out V P is also subjected to motive fluid pressure for actuating the valve.

In accordance with this construction, when the piston is in the position asshown in Figure 1, and about to start on its forward stroke, the vah'e is thrown toits forward position and motive fluid entering the inlet J passes through the. passage V, past the reduced neck F of the piston shank,

through the passage X and through the port U to the rear end of the main bore B behind the piston head E for the forward stroke. Fluid. pressure in front of the mainheadE exhausts through'the ports T and'S during the entire stroke. The valve P owing tothe relationship of the ports, and passages, is prevented from being thrown until the pis ton has practically finishedits stroke thereby retarding admission of motive fluid to the front end of the main bore B. This is due to the factthat, as'shown in Figure 1,

no pressure is exerted on the forward face e of the valve until after the rearface L of the piston has advanced and uncovered the port 0, by which time the piston will be traveling at a high velocity and will nearly "have 'reached'the end of its stroke and the pressure of motive fluid beingexerted on the end of the valve -P must first overcome the inertia of the same and movethe valve before fluid can enter the forward end of the cylinder bore B by which time the piston "will have completed its forward stroke.

'When the valve moves to' the position indicated in Figure,2,- motive fluid is admitted "to the front end of the mainbore B and the piston returns on its rearward stroke and thecycle is repeated at the other end. By

maintaining motive fluid pressure on the end faces of the valve P for a sufficient time [during the piston stroke, I am enabled to accomplish the objects of my invention, and

it will be further seen that in case thevalve sticks or acts sluggishlyloss of fluid pressure through the exhaust-ports T and U is i prevented. j

I'claim': d v y 1 1. In a flu d operated percusslve tool, the combination of a cylinder having a main bore and a bore of smaller diameter, a differential piston having a head and ashank formed with areduced neck, means'for maintaining constant fluid pressure on the rearward end surfaceof said piston shank, ports and passageways'from'the bore of smaller diameter controlled by the piston for distributing fluid to the ends of the main and the; exhaust closed. K 3. In afluidoperated percussive tool, the,

v I my. hand. "bore, exhaust ports for the main bore, and a I combination of a cylinder having a main bore and'a bore of smaller diameter, a'differential P181301} having a head and a shank formed with a reduced neck, ports and passageways from the boreof smaller diametercontrolled by the piston for distributing fluid to the ends; of the main bore, exhaust ports for the main bore,;a valve chest, and a valve controlling said exhaust ports, the

said. passageways from the bore of smaller diameter for admitting fluid through the valve chest to the ends of the main bore leadmgto the ends of the valve chest and subjecting the end faces of the .val've'di-.

rectly to the motive fluid pressure, whereby admission of fluidto either end of the main bore is'prevented until thevalve is thrown combination of a cylinder having a main forward bore and re'arwardbore ofsmaller diameter, a differential plston reciprocating in said cylinder having a main head fitting 2. In-a fluid operated percussive tool, they the [main bore, and a shank-or extension formed With an intermediate reduced neck connecting full portions of the shank fitting the smaller bore, means for maintaining constant fluid pressure on the rearward end surface of the said piston shank, ports and passages from the bore. of smaller diemeter controlled by the said piston'shank'for distributing motive fluid to the forwardiand rearward ends of the main bore,. exhaust ports for the main bore and "affluid actuatedvalve for controlling said exhaust -ports,said

valve also acting to retard the admissionv of fluid to the front end of the main boreuntil v the valve has moved and closed the exhaust .to that end of the, cylinder in orderto afford, time "for the piston to finish itsstroke.

LEWIS o; Barnes. 1

'In testimony whereof, I have hereunto set 

